Interesting case. He can certainly claim his own expenses, and I would try claiming his wife’s as well. Remember the 6 year rule: that he can claim all his actual expenses so long as he will full-pay the balance in 6 years. I suspect at $120K a month he will have enough left to pay in full within 6 years. It can be found at IRM 22.214.171.124.1.
The big issue here is to get him to make his estimated payments, even if he has to do it monthly instead of quarterly, to stay current.